Whenever the different stories of a house belong to different owners, if the titles of ownership do not specify the terms under which they should contribute to the necessary expenses and there exists no agreement on the subject, the following rules shall be observed:
(1) The main and party walls, the roof and the other things used in common, shall be preserved at the expense of all the owners in proportion to the value of the story belonging to each;
(2) Each owner shall bear the cost of maintaining the floor of his story; the floor of the entrance, front door, common yard and sanitary works common to all, shall be maintained at the expense of all the owners pro rata;
(3) The stairs from the entrance to the first story shall be maintained at the expense of all the owners pro rata, with the exception of the owner of the ground floor; the stairs from the first to the second story shall be preserved at the expense of all, except the owner of the ground floor and the owner of the first story; and so on successively. (396)